Rearranges the elements in the array in such a way that value of the
element in kth position is in the position it would be in a sorted array.
All elements smaller than the kth element are moved before this element and
all equal or greater are moved behind it. The ordering of the elements in
the two partitions is undefined.

New in version 1.8.0.

Parameters:

kth : int or sequence of ints

Element index to partition by. The kth element value will be in its
final sorted position and all smaller elements will be moved before it
and all equal or greater elements behind it.
The order all elements in the partitions is undefined.
If provided with a sequence of kth it will partition all elements
indexed by kth of them into their sorted position at once.

axis : int, optional

Axis along which to sort. Default is -1, which means sort along the
last axis.

kind : {‘introselect’}, optional

Selection algorithm. Default is ‘introselect’.

order : list, optional

When a is an array with fields defined, this argument specifies
which fields to compare first, second, etc. Not all fields need be
specified.